To keep these structures in position for example on an operating site, anchoring means are for example used implementing a set of anchoring lines made up in whole or in part of chains, in particular at their ends.
Such lines are then for example arranged regularly around the structure to be moored or anchored, and extend between said structure and respective mooring or anchoring points, for example on the seabed.
One can then see that the mooring and anchoring lines, the first ends of which in the form of chains are attached on said mooring and anchoring points, rise to the floating unit and are associated therewith, through the chain entry guiding means.
These guide means are also known in the technical field as fairleads.
These fairleads are in fact mechanical devices that include fastening and attachment means on the floating structure and guide means for a chain.
These fairleads are also associated in one way or another with means for placing said chains under tension and means for locking the chains in order to moor said structure.
The tensioning means may for example include winches or windlasses or the like.
The systems for locking the chains are also called chain stoppers in the state of the art.
Different embodiments of these various means are already known in the state of the art.
Thus for example, document FR A 2,984,272 describes a fairlead for such an application.
Indeed and in general, this fairlead includes means for guiding the anchoring element, which assumes the form of a chain, and means for locking said chain in position, including means in the form of a locking jaw comprising two locking jaw elements that are movable, by maneuvering means actuated by control means, between the inactive position locking the translation of the anchoring element and an open position releasing said anchoring element.
Indeed, these jaw-forming means include two locking jaw elements that are moved by the maneuvering means actuated by the control means, between a closed active position locking the translation of the chain and an open retracted position releasing said chain.
Of course, other example embodiments of said fairleads are known in the state of the art.
However, all of these fairleads, and in particular the control means of the locking jaw-forming means, have one common point.
Indeed, they require the maintenance of an action and a command on an actuator to keep the jaw-forming means in an open position releasing the chain.
One can see that this presents a certain number of drawbacks in terms of the operating reliability of the system and maintenance of the power supply for example of a hydraulic or pneumatic actuator, etc., to obtain this unlocking and the release of the anchoring element.